What is a CAS-RN?
Chemical Abstracts Service uses their official Registry Numbers (CAS-RNs) to identify the over 27 million unique chemical substances. A substance can be known by many different names but it will have only one RN assigned to it. This means a substance can be precisely identified. A CAS-RN is the square-bracketed number [xxxx-xx-x] you will find associated with a substance in various print indexes, reference works, and databases. If you have a literature reference to a substance the RN may appear in the document. The ultimate repository that you have access to at Concordia is SciFinder Scholar. This database is accessible on Campus only. Otherwise, you can try a reference HANDBOOK or one of the following free Web tools: ChemFinder, ChemIDplus, NIST, or Sigma-Aldrich.
